DEVICE AND METHOD FOR DETECTING A SURFACE SHAPE ON THE HUMAN OR ANIMAL BODY

Abstract

The invention relates to a system and a method for detecting a surface shape of a human or animal body surface. A plurality of magnetic field sensors (2) arranged relative to one another in a sensor field (1) is placed on a plurality of surface regions of the body surface. A magnetic field generator (7) generates a magnetic field in the vicinity of the sensor field, so that a plurality of surface signals belonging to the surface regions are generated by using the magnetic field sensors (2). The surface signals serve as position signals with regard to the orientation and position of the magnetic field sensors in the magnetic field, so that the surface shape of the body surface is determined from the plurality of position signals of the magnetic field sensors (2) by using a signal processing unit (5).

Claims

1. A System for detecting a surface shape of a human or animal body surface, which comprises a sensor array (1) with a plurality of sensors, which is designed to scan the body surface at a plurality of surface areas and to generate a plurality of associated surface signals, and a signal processing unit (5) adapted to determine the surface shape of the body surface from the plurality of surface signals of the plurality of sensors, characterized by a magnetic field generator (7) for generating at least one magnetic field in the vicinity of the sensor field (1), and a plurality of magnetic field sensors (2) which form the sensor field (1) and are arranged with respect to one another so as to rest on the surface of the body, the magnetic field sensors (2) being designed to generate, as a surface signal, a position signal with regard to their orientation and position in the magnetic field, so that the signal processing unit (5) determines the surface shape of the body surface from the plurality of position signals.

2. The System according to claim 1, wherein the plurality of magnetic field sensors (2) are arranged in the sensor field (1) in a regular grid.

3. The System according to claim 1, wherein the multiplicity of magnetic field sensors (2) of the sensor field (1) are arranged in relation to one another in a deformable sensor plane.

4. The System according to claim 1, wherein cat least a part of the plurality of magnetic field sensors (2) of the sensor field (1) are connected in series with each other.

5. The System according to claim 1, wherein the plurality of magnetic field sensors (2) of the sensor field (1) are mounted in or on a textile material.

6. The System according to claim 5, wherein the textile material is stretchable.

7. The System according to claim 1, wherein the magnetic field sensors (2) are designed as Hall or as magnetoresistive sensors.

8. The System according to claim 1, wherein the magnetic field sensors (2) comprise two or more sensor units designed and arranged for a three-dimensional measurement.

9. The System according to claim 1, wherein the magnetic field generator (7) is designed as a three-axis magnetic field source.

10. The System according to claim 1, wherein the magnetic field generator (7) generates a magnetic field of strength 10 nT to 100 mT in the vicinity of the sensor field (1).

11. The System according to claim 1, wherein the sensor array (1) comprises a further plurality of pressure and/or temperature sensors adapted to determine a signal corresponding to a pressure and/or a temperature at a plurality of surface areas.

12. A method of detecting a surface shape of a human or animal body surface comprising: placing a plurality of magnetic field sensors (2) arranged relative to one another in a sensor field (1) on a plurality of surface regions of the body surface, generating at least one magnetic field in the vicinity of the sensor field (1), generating a plurality of surface signals belonging to the surface areas by using the magnetic field sensors (2), the surface signals being in the form of position signals with respect to the orientation and position of the magnetic field sensors in the magnetic field, and determining the surface shape of the body surface from the plurality of position signals of the magnetic field sensors (2) by using a signal processing unit (5).

13. The Method according to claim 12, wherein the magnetic field sensors (2) are mounted in or on a textile material which is placed on a body surface in such a way that the plurality of magnetic field sensors (2) come to lie on a plurality of surface regions of the body surface, the magnetic field sensors (2) aligning their position according to an orientation and position of an associated surface region.

14. The method of claim 13, wherein the textile material is stretched over the body surface so that a predetermined distance of the magnetic field sensors (2) from each other changes.

15. The Method according to claim 12, wherein a digital data set (8) of a peripheral surface of the human or animal body surface is created from the plurality of position signals.

16. The system of claim 2, wherein a grid spacing of grid rows is variable.

Description

[0035] The invention is illustrated below with the figures, which serve merely to explain and are not to be interpreted in a restrictive manner. The features of the invention which become apparent from the figures need to be regarded individually and in any combination as belonging to the disclosure of the invention. What is shown is:

[0036] FIG. 1 is a schematic representation of a first variant of a sensor field of a system for detecting a surface shape of a human or animal body surface according to the present invention,

[0037] FIG. 2 is a schematic representation of a second variant of a sensor field of a system for detecting a surface shape of a human or animal body surface according to the present invention, and

[0038] FIG. 3 is a flow chart of a method for detecting a surface shape of a human or animal body surface according to the present invention.

[0039] As shown in FIG. 1, according to the invention a system for detecting a surface shape of a human or animal body surface is provided which comprises a sensor field with a plurality of magnetic field sensors. The sensor field is provided for covering a three-dimensional body surface, so that the body surface is subdivided into a multiplicity of surface regions. Each of the magnetic field sensors scans the surface region assigned to it and generates a position signal with information on its position on the body surface. Thus, a plurality of surface signals corresponding to the plurality of magnetic field sensors and associated surface regions are generated.

[0040] As can be seen in FIG. 1, the sensor units are integrated into a carrier 4 in the form of a flexible or extensible printed circuit board (PCB). The magnetic field sensors 2 are thus provided as three-axis magnetic field sensors. The magnetic field sensors 2 each generate a position signal with information about the orientation of the respective sensor with respect to the body surface and advantageously also about the local position of the magnetic field sensors to each other.

[0041] As can be seen from FIG. 1, the magnetic field sensors 2 are arranged in the sensor field 1 in a grid with predetermined regular distances from one another. The grid can be realized, for example, by attaching the magnetic field sensors in a textile material (not shown). Conductors (not shown) for relaying digital position signals of the magnetic field sensors may also be provided in or on the textile material. The sensors are advantageously connected in series, so that not all sensors are connected to one another and material can be saved.

[0042] In an advantageous variant of the detection system according to the invention, the sensor field forms a deformable sensor plane, as is indicated in FIG. 1. For this purpose, for example, the textile material on which the magnetic field sensors are arranged can be flexible and stretchable, so that the orientation of the individual magnetic field sensors to each other and also their distance from one another are variable. The sensor plane can thus adapt to any desired shape of a body surface and align the magnetic field sensors in accordance with the orientation of the respective surface regions. As indicated in FIG. 1c, the sensor plane shown is, for example, bulged outwardly from the plane of the drawing.

[0043] FIG. 2 shows an alternative embodiment of a system for detecting a surface shape of a human or animal body surface, where the magnetic field sensors are placed in series. The magnetic field sensors 2 are connected in series with four lines 3 and form a kind of sensor chain. The sensor chain can in turn be attached to a textile material. In the example shown, the sensor chain is bent in such a way that three essentially parallel rows result, which together form a sensor plane. In this way, a large number of magnetic field sensors and only a few lines are provided in the system.

[0044] FIG. 3 shows a diagram for carrying out a method for detecting a surface shape of a human or animal body surface according to the present invention. A signal processing unit 5 sends an activation signal to power electronics 6 in order to activate a magnetic field generator 7. In this variant, the magnetic field generator 7 is provided, for example, as a three-axis magnetic field source, such as, for example, in the form of a three-axis coil.

[0045] The magnetic field generator 7 generates a magnetic field in the vicinity of the sensor field 1. The magnetic field thus surrounds the multiplicity of magnetic field sensors 2, which belong to the multiplicity of surface regions of the body surface, and triggers a magnetic excitation of the magnetic field sensors 2. The magnetic field sensors 2 generate a surface signal in response to the magnetic field excitation in accordance with the magnetic field strength and their angular orientation and position in the magnetic field, which in turn depend on their orientation in accordance with the body surface and their distance from one another. This information can be determined on the basis of physical laws relating to the decrease in the magnetic field strength with the distance to the magnetic field source and the angular orientation in the magnetic field. This information is then sent by the plurality of magnetic field sensors 2 as a plurality of position signals to the signal processing unit 5. The position signals thus map the orientation and the extent of the surface regions, so that the signal processing unit 5 can determine the shape of the body surface therefrom and output it as a digital data set 8 of the surface shape. This digital data set can, for example, be fed directly to a CAD program for constructing an orthopaedic aid.

[0046] Although the detection method has been explained with reference to an example of a static surface shape determination, it is, with the system and the method according to the present invention, quite possible to carry out a dynamic shape determination where the shape of a body surface changes, for example, in accordance with a movement of a patient during the scanning. It is merely necessary to ensure that the patient moves within the magnetic field generated by the magnetic field generator. As a result, it is possible, for example, to determine the snug fit of orthopaedic aids during a movement of the patient.

[0047] The system and the method for detecting a surface shape of a human or animal body surface according to the invention thus have wide-ranging possible applications and can at the same time be used in a cost-effective and energy-saving manner. In addition, they permit a high degree of accuracy of the surface shapes detected. In particular, a closed surface model can be produced, for example, around a hand, an arm, a foot and the like, as is frequently required in orthopaedic technology.

REFERENCE SYMBOL LEGEND

[0048] 1 Sensor field [0049] 2 Magnetic field sensors [0050] 3 Lines [0051] 4 Beams [0052] 5 Signal processing unit [0053] 6 Power electronics [0054] 7 Magnetic field generator [0055] 8 Digital dataset